Boiler-furnace



(No Model.) 2 Sheets-Sheet 2. T- G. HARRIS. BOILER FURNACE.

No. 579,233. PatentedMar. 23, 1897.

THOMAS OORNFIELD HARRIS, OF PIERRE, SOUTH DAKOTA.

BOILER=FURNACE.

SPECIFICATION forming part of Letters Patent N 0. 579,233, dated March23, 1897'.

- Application filed February 23, 1893. Serial No. 463,354. (No model.)

To all whom zit may concern.-

Be it known that I, THOMAS CoRNnIELD HARRIS, a citizen of the UnitedStates, residing at Pierre, in the county of Hughes and State of SouthDakota, have in vented certain new and useful Improvements inBoiler-Furnaces, of which the following is a specification.

My invention, as its title indicates, relates to furnaces for heatingsteam-boilers, which may be of any form or description and applied toany of the purposes to which steam-boilers are applied, such asproviding steam for stationary or locomotive or marine engines, or forsteam-heating systems for domestic and industrial purposes.

The furnace involved in my invention may also be applied to otherpurposes besides heat ing steam-boilers, and may be used in connectionwith air-heating and metallurgical plants, dtc.

The object of my invention is to provide means whereby the smoke orunconsumed carbon evolved from the fuel, such as bituminous coal, at thebeginning of the combustion, when the furnace is freshly stoked, andwhich is due to imperfect combustion, will be completely consumed orconverted into carbon dioxid before it leaves the furnace. For thispurpose a furnace embodying my invention consists of a supplementalhearth or fireplace arranged in advance of the main grate of thefurnace, preferably projecting from and overhanging the usual or singlefront wall of the furnace, in which supplemental hearth or fireplace thefuel undergoes a preliminary combustion until the same ceases to evolvefree carbon or smoke, when the said fuel is pushed forward, so as todrop into the main grate.

A furnace embodying my invention also comprises, in connection with theabove, a rear wall extending from the top of the furnace-chamber down toand within a short distance of the main grate, where a sufficientopening or outlet for the products of combustion into the smoke-flue orchimney is left.

By this means the incompletely-consumed products of combustion and smokefrom the supplemental hearth are compelled to pass into close proximitywith the intense fire in the main grate, where they are completelyconsumed.

My invention, moveover, consists ofsuch features, details, andcombinations of parts as will be described hereinafter and pointed outin the claims.

In the drawings annexed to this specification, Figure 1 represents alongitudinal vertical central section of a boiler-furnace embodying myinvention in its preferred form. Fig. 2 is a vertical transverse sectionthereof on line 2 2, Fig. 1; Fig. 3, a sectional plan taken on line 3 3,Fig. 2; Fig. 4-, a front elevation of the furnace, and Fig. 5 a verticaltransverse section of a somewhat modified form of furnace.

The furnace illustrating my invention is shown in connection with whatis known as a horizontal-flue boiler, the products of combustion fromthe main hearth A of the furnace passing by way of a vertical fine athrough the horizontal boiler-fines a from rear to front of boiler tothe chimney-flue a in a well-known manner. As already stated, any othersuitable or desired form of boiler and furnace maybe employed instead.The furnace-chamber A is provided at its bottom with a grate B of anysuitable or desired form and construction and forming the main hearth ofthe furnace. Below the grate B is located the ordinary ash-pit C.

One feature of myinvention consists in providing the furnace with a supple mental hearth D, preferably overhanging the front wall A of thefurnace, so as to be entirely outside of the furnace-chamber A. Thishearth may be of various constructions and arrangements, but ispreferably located directly below the chimney-fine a so as tofurtherheat-theprodnets of combustion as they enter said flue, and henceto accelerate the draft.

I preferably construct and arrange the supplemental hearths as follows:A bottom plate (Z, of iron or other suitable material, is supported bythe front wall A of the furnacechamber and upon a supporting rail orbeam cl, extending across the furnace in advance of the front wall A andsupported by the side walls A of the furnace, which for this purpose arecontinued beyond the front wall A as shown best in Fig. 1. On both sidesXCO of the bottom plate d I arrange an inclined grate E, whichpreferably consists of a terraced series of grate bars or gills e, eachof which is inclined inwardly toward the center of the hearth, as shownin Fig. 2. These grate-bars forming the terraced grates are supported inany suitable way, preferably by lugs 6, arranged on the win gs risingfrom the front wall A and on the front wall D of the supplementalhearth. It will be observed that this construction results in a recessor open chamber below the supplemental hearth, in front of the frontwall A and between the side walls A A, from which chambers the air tosupport the combustion passes over the outer edges of and downwardlybetween the slotted openings c ,between the grate-bars e, as indicatedby the arrows in Fig. 2. The front wall A above the base-plate (Z, isbroken away, so as to carry the smoke and products of combustion intothe furnace-chamber A.

A door D for firing is arranged, as usual, in the front wall of thesupplemental hearth D, and stoke-holes a a are formed in the front wallA substantially on a line with the grate-bars B.

The rear wall A of the furnace, which may be constructed of fire-brickor other refractory material, extends down to near the bottom of thefurnace-chamber A, where it is formed with an opening a of sufficientsize to permit the products of combustion to escape into the flue a.This opening is best con structed by forming an arch a at the bottom ofthe rear wall A close to the grate-bars B. (See Figs. 2 and 5.)

The object of making the rear wall extend down into proximity with thegrate is to compel the smoke and free carbon evolved from thesupplemental hearth D to descend and pass into close contact with theintense fire on the main heartlnwhere they are completely consumed.

In Fig. 5 I have represented a slightlymodified form of boiler-furnacewhich differs from that already described only in that two supplementalhearths D D are here employed. In all other respects the construction isprecisely the same.

The operation of my furnace is as follows, it being assumed that thefire in the main hearth is in the proper condition and it is necessaryto add fuel: The supplemental hearth is charged with fuel, such asbituminous coal or the like. This fuel at first slowly evolves aconsiderable amount of free carbon and gas in consequence of incompletecombustion. This smoke or free carbon in its passage to fine a issupplied or mixed with a sufficient quantity of oxygen through thesupplemental grate to render it highly inflammable, and in thiscondition is deflected downwardly by rear wall A and so brought intocontact with the intense fire on the main hearth B, where it iscompletely consumed. Then the fuel on the supplemental hearth ceases toevolve free carbon, the stoker pushes it off from the bottom plate (1,causing it to fall upon the main grate B, where it is arranged andspread in the proper manner, the stoke-holes a a permitting ready accessto the stoking implements employed for this purpose.

From the foregoing it is shown that a f urnace embodying my inventionmay be greatly and variously modified without departing from myinvention and that the same is not confined to any particular form offurnace.

I do not, therefore, desire to be confined to the details ofconstruction and arrangement set forth; but

lVhat I claim as my invention, and desire to secure by Letters Patent,is-

1. In a furnace, a main grate in combination with a supplemental hearthconsisting of a base-plate and an inclined grate arranged on each sideof the base-plate, substantially as set forth.

2. In a supplemental hearth for furnaces,the combination, with abase-plate, of a terraced series of grate-bars, each of which isinclined toward the center of the hearth, substantially as set forth.

3. In a f urnace,the combination with a main hearth of a supplementalhearth, overhanging the front wall of the furnace and consisting of abase-plate and a terraced series of gratebars, arranged on each side ofthe base-plate, substantially as set forth.

In testimony whereof I affix my signature in the presence of twowitnesses.

THOMAS CORNFIELD HARRIS.

IVitnesses:

FRANK A. KEYS, G. N. LUKEs.

